Field of Invention
The present invention relates to the field of liquid crystal display technology, and more particularly to a liquid crystal display for a GOA (Gate Driver on Array, an array substrate row driver) circuit based on LTPS (Low-Temperature Poly-Si) CMOS (Complementary Metal Oxide Semiconductor).
Description of Prior Art
Touch panels have been widely applied in smart phones, tablets/electronic books, electronic notebooks, POS (point of sale)/KIOSKs, game consoles, and ATMs. In the future, the number of touch panels will quickly increase, especially in cell phones, tablets, portable media players (PMP/MP3), personal pilot devices, and other applications. Meanwhile, touch panels will have a chance to break out and grow into large-size-screen applications such as All-In-One computers.
According to an output volume of touch panels, mobile phones are the most important field (where ⅔ touch panels are applied), especially with the perfervid competition of cost-concerned market and the demand for high quality products, an in-cell touch technology has been grown. For touch technology, the report rate is an important index; the report rate generally needs to be higher than a specific number (60) to pass a technical request. The format of scanning decides the report rate which influences the sensitivity of the touch panel directly. However, the format of scanning is limited by the time limit of the frame rate and the gate scanning driving format.
Usually, for touch technology, the formats of driving electrodes (Tx) are divided into two kinds. One is to scan the driving electrodes at the blanking time after the display image has scanned; however, take display devices with 60 Hz, the time for scanning the driving electrodes is less than 4 ms.
Another format is to scan the driving electrodes at the gaps between the output gate signals during the column scanning procedure. In order to avoid the interference of the signals of the driving electrodes caused by the data signal, a scanning of the driving electrodes needs to be done at the flat region of the data signal. For a high resolution product, the time required for the scan is extremely short, the width of each signal of the driving electrode is less than 2 us. The time is too short to accomplish the scanning of the driving electrodes, especially while trying to coordinate the touch technology with a normal display driving method, which is a large scanning limit to the touch technology. This makes a 120 Hz or higher scanning format report rate hard to accomplish. Thus, the report rate will be lower than the limit of this format.
For medium and small display devices, especially for LTPS products which are applied with the GOA design, GOA, which is using the existing array process of TFT (Thin Film Transistor) liquid crystal display to manufacture the gate scanning signal circuits on the array substrates. The GOA is a technology to accomplish the cascade scanning on gate electrodes. For the issue of panel power consumption, CMOS circuit design is applied in most of the manufacture processes of LTPS in the industry.
The present invention provides a CMOS gate driving circuit based on LTPS, with scanning circuit structure and scanning format, in order to improve the format of touch scanning, increase the report rate of a touch panel, and to improve the sensitivity of the touch panel.